Thermowood Feather Edge Cladding

Thermowood was developed as an eco-friendly, chemical free alternative to standard pressure treated softwood and has quickly become a trade favorite for cladding and other projects that require durable and stable timbers.

Using a high grade Scandinavian Redwood at its base, Thermowood is treated using special kilns at extremely high temperatures to produce a very low moisture and stable product. Featuring many knots, Thermowood offers a very traditional wood aesthetic perfect rustic projects.

We use a featheredge profile with a 20mm rebate to not only capitalize on the low cost and traditional aspect of featheredge cladding but also the extra stability and protection that comes with rebating.

How Long Does Thermowood Cladding last?

The BRE (Building Research Establishment) expect a 30 year service life when properly installed as a cladding product. Furthermore, thanks to its unique treatment process, it is completely stable in temperatures from –40 degrees to 40 degrees.

Does Thermowood Need Treating?

As it has been heat treated initially, further surface treatment isn’t necessary. That said, customers are welcome to add any stains, finish or paint to transform the cladding to suit their exact needs as it takes paint extremely well.

Painting Thermowood is also a good way to protect it from the elements and any UV bleaching from the sun.

If left untreated, Thermowood like all other timbers will go silver-grey overtime.

Can Thermowood Be Used in Sauna’s?

Thermowood is perfect for a sauna environment due to its exceptionally low moisture content and stability. It is often used in place of the expensive Western Red Cedar due to its much more reasonable price range and better thermal efficiency, which is around 25% more effective.

Initially developed by Finland – the country known for having the highest number of saunas per household – it is no surprise that Thermowood is one of the best options available for saunas.

For Thermowood to use in a Sauna, check out our Tongue & Groove Thermowood range.

Fitting Guidance

Our Feather Edge Cladding is designed to be installed by a professional with previous experience in successfully fitting it. The information here is provided as an overview only and is not a substitute for professional fitting advice.

Be sure to read our treatment guidance as treatment needs to be applied prior to fixing your cladding

Breathable Membrane

Consult a fitter to determine if your scenario would require the fitting of a breathable membrane between your wall and the cladding. This membrane stops rain getting to the wall, but allows moisture to escape, helping to prevent internal condensation and mould that can come with it.

Treated Softwood Battens

Treated softwood battens (available from our cladding accessories pages) are most commonly used to fix to the wall (or on top of the breathable membrane) to then fix your cladding to. Feather Edge Cladding is for horizontal fixing only, so your battens need to be placed vertically, at around every 600mm (60cm).

Fixing the Cladding

** Whether you use nails or screws, it's important that they are stainless steel, or silicone bronze ARS, so that the natural tanins in the timber will not corrode them. Never use iron nails for fixing timber.

There are two common ways to fix feather edge cladding. The first is to nail it, in which case it's best to use two nails across the width of the board (so one vertically above the other), as long as you don't nail through two boards at once with the same nail, so it won't split as it expands or contracts with the seasons. If you use nails, preferably use ring-shanked for extra grip, and again stainless steel so they don't corrode. For lower-density species like cedar, consider using nails with larger heads so the cladding doesn't pull through.

Secondly, you can pre-drill holes wider than the body of the screws you are using, and hold the boards with the head of the screw. This will allow movement without splitting the boards.

Either way, start at the bottom and use an extra batten to space the bottom of the bottom board away from the building. Work your way up the building. Make sure you have the thinnest part of the board at the top.

Layout of the cladding

With each new row of cladding you add, it's preferred that you stagger the joins between each board so you don't create a visible seam.

As already stated, these are just ideas to get you thinking about installation and you should consult a professional installer before fitting your cladding as every scenario is different.

All our claddings are provided untreated. Fresh sawn timber claddings are best left untreated and to go silver grey. There are a wide range of optional treatments available for different species of timber and we recommend talking to the excellent team at www.wood-finishes-direct.com, who know the most up-to-date information on all the newest treatment products.